How to use a PPlot?

How to use a PPlot?

In the code snippets below it is assumed that you have declared a variable of the main class (PPlot)

PPlot mPPlot;

A simple plot

You make a plot by supplying datasets for x and y. A datataset (PlotData) is an stl container of floats.

// make x/y datasets for one plotitem PlotData *xdata = new PlotData ();
PlotData *ydata = new PlotData ();
// fill them as any stl container (with floats)
for (...) {
xdata->push_back (...);
ydata->push_back(...);
}
// add item to the plot
mPPlot.mPlotDataContainer.AddXYPlot (xdata, ydata);// takes ownership

Two plot items with legend data

You can have multiple plotitems in one plot. You simply make and fill datasets and legend info as follows

PlotData *xdata1 = ...;// see above how to make two x/y datasets PlotData *ydata1 = ...; PlotData *xdata2 = ...; PlotData *ydata2 = ...; LegendData *legend1 = new LegendData ();// let us setup the first legend legend1->mName = "foo"; legend1->mColor = PColor (100,200,200);// just an rgb value LegendData *legend2 = ...;// do something similar for the second legend // add the plotitems mPPlot.mPlotDataContainer.AddXYPlot (xdata1,ydata1, legend1); mPPlot.mPlotDataContainer.AddXYPlot (xdata2,ydata2, legend2);

Plot region (setting margins)

A plot consists of a plot region surrounded by margins. In the picture below, the plot region is the dark gray area. As you can see some things are drawn outside the plot area. If you would put all margins to zero you would only see the plot area and the title and y-axis ticks would fall outside the widget.

Margins can be set manually with

mPPlot.mMargins.mLeft = 20;
mPPlot.mMargins.mRight = 20;
mPPlot.mMargins.mTop = 20;
mPPlot.mMargins.mBottom = 20;

Axis setup

You can influence the way the axes are drawn through the two axis setup members

mPPlot.mXAxisSetup; mPPlot.mYAxisSetyp;

You can turn of autoscaling and provide a customized range for an axis (for instance the x axis) like this

mPPlot.mXAxisSetup.SetAutoScale (false); mPPlot.mXAxisSetup.mMin = -5; mPPlot.mXAxisSetup.mMax = 3;

You can use autoscale to the maximum of your data but keep the minimum at a fixed value like this

mPPlot.mXAxisSetup.mAutoScaleMin = false;// do not change the minumum mPPlot.mXAxisSetup.mMin = 0;
mPPlot.mXAxisSetup.mAutoScaleMax = true;// do change the maximum according to data

Logarithmic scale is achieved with

mPPlot.mXAxisSetup.mLogScale = true;mPPlot.mXAxisSetup.mLogBase = 10;// 10 is the default

By default an axis goes through the origin. As a result it may become invisible. You can prevent this with

mPPlot.mXAxisSetup.mCrossOrigin = false;// this way the axis will always be visible

You can give the axis a label with

mPPlot.mXAxisSetup.mLabel = "bar";

To change the direction in which the data run with respect to screen coordinates you can specify

mPPlot.mXAxisSetup.mAscending=true;// default: left is minimum, right is maximummPPlot.mYAxisSetup.mAscending=false;// default : bottom is minimum, top is maximum

Title and background color

You can give the plot a title and a background color with

mPPlot.mPlotBackground.mTitle = "nice curves"; mPPlot.mPlotBackground.mTransparent = false; mPPlot.mPlotBackground.mPlotRegionBackColor = PColor (3,100,130);

Grid

A grid is drawn when you state

mPPlot.mGridInfo.mXGridOn = true; mPPlot.mGridInfo.mYGridOn = true;

Indexed plot data

Quite often you don't care about xdata: they shoul just be increasing numbers. You can create such a set with

PlotData *theYData = ... // fill ydata here DummyData *theXData = new DummyData (theYData->size ());// make the indexed data mPPlot.mPlotDataContainer.AddXYPlot (theXData, theYData);

An even more simple solution is to supply a null value as xdata

mPPlot.mPlotDataContainer.AddXYPlot (0, theYData);

Data with strings

Sometimes your data can take on some discrete values that are conveniently described with strings (for instance weekdays and months). You can make such a dataset like this

StringData *theStringData = new StringData (); for () { theStringData->AddItem ("string i here"); }

the end.